1. Field
An aspect of the present invention relates to a battery pack.
2. Description of the Related Art
Recently, compact and light portable electronic/electric apparatuses such as a cellular phone, a laptop computer, and a camcorder are actively developed and produced. Battery packs are built in the portable electronic/electric apparatuses so that the portable electronic/electric apparatuses may operate in places where power sources are not provided. Battery packs using economical rechargeable secondary batteries such as a nickel-cadmium (Ni—Cd) battery, a nickel-metal hydride (Ni-MH) battery, and a lithium (Li) battery are commonly used.
Among the battery packs, the battery pack using the lithium secondary battery has an operating voltage three times higher than that of the battery pack using the Ni—Cd battery or the Ni-MH battery and has a high energy density per unit weight so that the battery pack using the lithium secondary battery is widely used in the portable electronic/electric apparatuses. The lithium secondary battery is classified as a lithium ion battery that uses liquid electrolyte and a lithium-polymer battery that uses polymer electrolyte in accordance with the kind of electrolyte used. Further, the lithium secondary battery is classified as a cylindrical type battery, a prismatic type battery, and a pouch type battery in accordance with a manufactured shape.
Generally, the battery pack using the lithium secondary battery includes a bare cell, a protective circuit board electrically connected to the bare cell to prevent the overcharge and over-discharge of the bare cell. In order to fix the bare cell to the protective circuit board, in general, a molding process of filling a space between the bare cell and the protective circuit board with a molding material such as resin or hot melt is performed. The bare cell is formed by accommodating an electrode assembly in a can having a top opening and by sealing the top opening of the can by a cap assembly. The electrode assembly includes a positive electrode plate and a negative electrode plate each having an electrode tab connected to a collector coated with electrode active materials and a separator positioned between the positive electrode plate and the negative electrode plate.
The battery pack is charged with a preset capacity and shipped. When an end user uses the battery pack for the first time after a shipping period, the user may use the battery pack without charging the battery pack. The shipping period is defined by a time period from the time when the manufacturing of the battery pack is completed and shipped to the time when the end user mounts the battery pack in an apparatus. That is, the shipping period of the battery pack is from the time when the battery pack is shipped to the time when the end user purchases the battery pack in order to mount the same in the apparatus. However, the shipping periods of the battery packs may be variable. When the shipping period of the battery pack is extended, since the charged battery pack may be completely discharged due to internal current consumption of the battery pack, the end user must recharge the battery pack before the first use.